Yes! that Timotheus whom I have known from boyhood, so intent upon an upright and ascetic life, as even to be accused of excess therein, now forsakes the enquiry after those means whereby we may be united to God; now makes it his first thought what some one else may think of him, and lives a life of dependence upon the opinions of others; is mainly anxious how to serve his friends, without incurring the ridicule of enemies; and fears disgrace with the world as a great misfortune.  Does he not know, that while he is occupied with these trifles he is unconsciously neglecting his highest interests?  For, that we cannot be engaged with both at once—the things of this world and of Heaven—the holy Scriptures are full of teaching for us.  Nay, Nature herself is full of such instances.  In the exercise of the mental faculty, to think two thoughts at the same time is quite impossible.  In the perceptions of our senses, to admit two sounds falling upon our ears at the same moment, and to distinguish them, although we are provided with two open passages, is impossible.  Our eyes, again, unless they are both fixed upon the object of our vision, are unable to perform their action accurately.